Battlezone is a 3D action game. The story is that of a 1950's meteor shower where American and Soviet scientists simultaneously discovered an off-world bio-metal, which they could fabricate into amazing vehicles and weapons. This began the space race for rare metals, which eventually leads into war.
A first person shooter/stealth game crossed with an RTS. There's an argument to be made that this is the best video game ever devised. Like nothing else I've found.